Coil expander



Au 9, 1966* n. mm 3,265,321;

CO'IL EXBANDER Original Filed Jude 2a,- 1952 United States Patent 3,265,321 COIL EXPANDER Richard Rahn, Dusseldorf, Germany, assiguor to Schloernann Aktiengesellschaft, Dusseldorf, Germany Original application June 28, 1962, Ser. No. 205,975, now

Patent No. 3,216,671, dated Nov. 9, 1965. Divided and this application May 18, 1965, Ser. No. 456,776

Claims priority, application Germany, July 25, 1961,

Sch 30,037 6 Claims. (Cl. 2427S.1)

This application is a division of SN. 205,975, filed June 28, 1962, now Patent No. 5,216,671.

Cold rolled metal strip delivered from the rolling mill is usually extremely hard and consequently must be annealed in a suitable gaseous atmosphere prior to delivery to the customer. Since the strip is normally tightly coiled, annealing of such a coil provides non-uniform results and, therefore, various methods and apparatus have been devised to overcome this problem.

For the winding of thick and brittle metal strips, socalled reel-less winding machines are known, which comprise a set of bending rollers, by which the strip is bent in such a way that it roll-s up into a spiral. Strip coiled in this way is usually very loose, and under some circumstances exhibits gaps between the individual turns. These gaps however are irregular and undefined. Moreover, this method of winding can only be used for short strips, that is, for small coils, since the stiffness of the strip is insufficient to continue turning around rings of strip that have become heavy. This is also the case when one provides further positively driven rollers in the guide that received the loosely coiled spirals of strip. Furthermore, injuries to the surface are very liable to occur owing to the individual turns exerting a grinding action on one another.

For thin metal strips a method of winding has become known in which one first winds at normal coil, which is subsequently loosened in that while keeping the direction of winding unchanged and approximately maintaining the external diameter of the coil, the winding operation is continued at the inner end of the strip with a reduction of the internal diameter of the coil. Scratching or other surface injuries to the strip are here inevitable, owing to the turns grinding upon one another. Also accurately defined spaces between the turns are not attainable.

Finally, for the re-shaping of coils of strip iron of a given diameter to a larger diameter, apparatus is already known, in which the coil of strip to be re-shaped is placed upon a stationary table, the outer end of the strip being secured to the internal peripheral surface of a clamping ring embracing the coil, and the clamping ring being set in rotation in a direction opposite to the winding direction of the coil whereby the'individual turns of the coil come progressively into contact with the rotating clamping ring in an inward direction. With such apparatus for centering the coil one will preferably provide a central mandrel for receiving the coil. In order to carry out the winding operation it is of course possible to rotate the central mandrel, with the tightly wound coil thereon, instead of the outer clamping ring; or the central mandrel, with the tightly wound coil thereon; and the external clamping ring, may be rotated in opposite directions, whereby the re-winding operation will be considerably accelerated.

By re-winding with such apparatus as this, the high tensile stress usually prevailing in a tightly wound coil can be considerably diminished, that is to say, coils that are quite loose and soft can be produced. How loose the newly formed coil will be depends chiefly upon the frictional resistances acting upon the strip during the rewinding operation. Now in order to enable these fric- "ice tional resistances, which arise particularly owing to the outwardly travelling turns grinding upon the support, to be better and more accurately influenced, one might also make the supporting surface rotatable, and provide it with a drive of its own, so that this surface, during the winding operation, can be set in rotation slowly or quickly, in the same direction as the other parts of the apparatus or in the opposite direction, according to requirements. In this way the strength of the newly formed coil could be more accurately controlled. Nevertheless it would not be possible, even by these arrangements, to obtain definite distances between the individual turns. The turns will touch and bear upon one another.

The problem faced by this invention is consequently to produce an opened coil with spaces between the individual turns, the distances between the turns being uniform and being as accurately defined as possible. As regards apparatus, the invention might be regarded as a further development of the re-winding apparatus last described, and so, proceeding in a known manner, name- 1y with the coil standing on end upon a supporting surface, and with the inner end of the strip being held fast, to bring the outer end of the strip to a point spaced from the centre of the coil corresponding to the radius of the opened coil, and there to set it in rotation in a direction opposite to the winding direction of the coil, so that turn after turn is drawn off from the tightly wound coil and is moved outwards towards the outer end of the strip. The apparatus needed for this operation has already provided satisfactory results. It is very simple in construction, is economical in the space occupied, and is very reliable in operation, particularly with respect to injuries to the surface of the strip. Above all, the unwinding and re-winding of the strip that is otherwise usual in the production of an opened coil is obviated.

As regards method, the invention goes back to magnetic spreading known in itself, and proposes that the turns loosening from the tightly wound coil and travelling outwards, are magnetized in the region in which the coil of larger diameter is being formed, this being done in such a way that the edges of the strip on one end face of the coil acquire the same polarity.

For the state of the art, however, the following is to be mentioned: It is known that magnetic bodies of the same polarity repel one another. Extensive and varied technical use has already been made of this fact. Thus for example appliances havebecome known for unstacking iron sheets, wherein, by properly magnetizing the stack of sheets, those sheets that for the time being are lying uppermost are lifted off and detached from the stack by magnetic force. For the production of the magnetic field necessary for this purpose, both permanent magnets and electromagnets are known, or even magnet coils, which are then arranged in such a way that the field of the coil runs through the stack as a magnet core. The possibility of converting a tightly wound coil of strip, coming for instance from a cold-rolling mill, by means of the so-called magnetic spreading, into an open coil of strip with accurately predetermined distances between the individual turns, for the annealing operation, has never yet been contemplated, and has not been rendered obvious by the state of the art. Open coils of strip with accurate spaces between the individual turns have hitherto always been produced by unwinding and re-winding the strip.

The method according to the invention will now be further explained with reference to the accompanying drawings. These drawings are diagrammatic views, which are limited merely to representing those parts that are important for the comprehension of the invention, a number of constructional details, the incorporation of which lies within the knowledge of an average technologist, being omitted.

In these drawings, FIGURE. 1 is a side view in sectional elevation of the apparatus according to the invention; and

FIGURE 2 is a plan view.

Upon a circular solid base-plate 1 are mounted a relatively large table-like plate 2 and a smaller ring 3. Whilst the outer and larger table-like plate 2 is rotatably supported, the inner and smaller ring is nonrotatable, being secured fast to the base-plate 1. The table-like plate 2 is raised stepwise towards the periphery, to form a circular upward projection 2a, and a collar 2b projecting above the latter. The level inner portion of the plate 2 carriesa number of individual rings 4, 5, 6 and 7 of different sizes, which lie one within another, and which can turn independently of one another by sliding upon the plate 2. The construction and arrangement of these rings is such that the upper surfaces of all the rings are flush with one another, so that a plane supporting surface is formed for the accommodation of the coil of strip 8 to be re-shaped. Within the stationary ring 3, and at the centre of the base plate 1, is provided a vertical core or mandrel 9, which serves as a pivot, and which is equipped with a clamping device 10 for the inner end of the coil of strip. The plate 2 can be driven preferably in either direction, by any convenient driving means, for instance, as indicated in the drawings, by way of a pinion 11 meshing with teeth on the collar 2b. The plate 2 also carries a cylindrical outer casing 12, which is held by the collar 2b, and is provided with a number of vertical slots 13 distributed round its periphery, in which block magnets or bar magnets 14 are so mounted as to be adjustable in height.

On the central mandrel 9 is mounted a ring 17 of substantially channel shaped cross section with the opening of the channel facing outward. The ring 17 is axially slidable up and down along the mandrel 9, but is prevented from turning relatively thereto by a key 18 engaging in a vertical longitudinal groove 19 machined in the mandrel.

In the outwardly opening channel of the ring 17 there is rotatably disposed a wheel hub 20 having four spokes or arms 21 extending radially outward therefrom. Radially extending screw threaded spindles 22 are juornallled in downwardly extending flanges on the wheel hub and spokes 21 with the spindles 22 disposed beneath the spokes 21. To the inner ends of these spindles are keyed bevel pinions 23 which mesh with bevel teeth on the lower edge of the channel shaped ring 17. The spindles 22 extend through the magnets 14 and engage with internal screw threads therein.

The method of operation of the apparatus according to the invention is as follows: The coil of strip 8 to be opened is placed upon the apparatus in the manner shown in the drawings, the inner end of the strip being clamped to the non-rotatable vertical mandrel 9. The cylindrical outer casing 12 is then placed upon the plate 2, and the outer turn of the coil of strip 8 is so far loosened to provide a sufficiently large circle to enable the outer end of the strip to be secured to the internal wall surface of the casing 12 by means of a clamping device, not shown, provided on the cylindrical casing 12. Ring 17, wheel hub 20 and spokes 21, the magnets 14 and spindles 22 are then slipped onto the mandrel 9 with the magnets 14 and the spokes 21 engaging in the slots 13. With the magnets almost resting upon the upper edge of the coil, but preferably with a clearance'of a few tenths of a millimeter between the magnets and the edge of the coil the spokes 21 are clamped to the casing 13 by means of clamping screws 24 passing through the slots 13 into upwardly extending ears 25 on the spokes 21. If the plate 2, and with it the outer casing 12 also, is now rotated, in the direct-ion of the arrow 16 for example, the outer end of the strip, which is secured to the casing 12, is also carried with it. The section of the strip that is travelling towards the stationary ring 3 in a spiral of large pitch is thus moved outwards, in an unwinding direction, towards the outer end of the strip, that is, towards the casing 12, while a corresponding fresh section of a turn moves away from the tightly coiled bunch of strip. The outwardly moving turns or turn sections then move into a position underneath the magnets 14, and thus pass into the range of action of the magnetic field emanating from the magnets, thereby inducing a magnetic pole on the edges of the steel strip. Since the edge of each freshly arriving turn, or each freshly arriving section of a turn, is magnetized with the same polarity, a repulsion occurs between the adjacent turns that are approaching one another, since like poles repel one another, thereby preventing the on-coming turn coming into contact with the turn already formed previously, thus producing the opened or expanded coil 8a. As the casing 12 revolves carrying the wheel hub 20, the spokes 21, the magnets 14 and the spindles 22 around with it, the bevel pinions 23 roll around the stationary bevel teeth on the ring 17 thus rotating the spindles 22 about their own axes and thereby moving the magnets 14 radially in the direction of the arrows 15 towards the still tightly wound portion 8 of the coil concurrently with the formation of the opened portion 8a of the coil so that the magnets 14 always project into the space intervening between the loosened turns and the turns that are still tight. The mechanism for moving the magnets 14 radially is conventional. As magnets, permanent magnets may preferably be employed, the field strength beingat the same time suitable for the size of the space between the turns. Electro-magnets that can be switched and regulated may however equally well be used.

It is preferably, as far as possible, to obviate a grinding action of the lower edge of the strip upon the supporting surface during the expanding operation and the individual rings 4, 5, 6 and 7 are provided for this purpose. As already described, the tightly coiled strip 8 located in the middle of the apparatus is stationary during the expanding operation. The individual rings supporting the stationary coil 8, for instance the rings 6 and 7, are here held fast by the weight resting upon them, so that while the plate 2 is being driven, the latter revolves beneath the individual rings. In the course of the expanding operation, turn after turn is then released from the stationary coil and moves radially outwards, so that one ring after another is relieved of load. The relieved rings 4, 5 and '6 are then each carried round from time to time by the revolving plate 2. The turns already released, rotating together with the casing 12, are thereby provided with a supporting surface rotating with them, which is virtually stationary with respect to their rotation.

After the completion of the expanding operation, the magnets 14 are moved radially outwards away from the upper edges of the strip and from the end face of the opened coil 8a. Any inequalities in the spacing of the turns are equalized at this time by the movement of the magnets. After releasing the outer and inner ends of the strip from the outer and inner clamping devices, the casing 12 is removed from the apparatus, and the expanded coil 8a can be lifted off the apparatus, by means of a strong magnet or other suitable means.

In order not to have to take special care regarding the position of the leading end of the strip, when placing the coil of strip upon the apparatus, it is advantageous to make the clamping device 10 provided on the mandrel 9, and the clamping device, not shown, on the casing 12, double-sided, so that a strip end coming from the right or a strip end coming from the left can be gripped. The apparatus must of course then be capable of being driven in either direction of rotation.

It will be obvious to those skilled in the art that various changes may be made in the invention and without departing from the spirit and scope thereof and therefore the invention is not limited by that which is shown in the drawing and described in the specification, but only as indicated in the appended claims.

I claim:

1. Apparatus for the conversion of a tight coil of magnetizable steel strip into an expanded coil with spaced turns, said apparatus comprising a stationary upright mandrel, a number of rings concentrically surrounding the mandrel, the upper surfaces of said concentric rings forming a continuous plane supporting surface upon which a coil of strip can rest, a cylindrical outer casing concentric with the mandrel, driving means for rotating the outer casing relatively to the mandrel, and a plurality of bar magnets extending radially into the space intervening between the loosened outer turns of the bunch and the still tightly coiled inner turns.

2. Apparatus for the conversion of a tight coil of magnetizable steel strip into an expanded coil with spaced turns as claimed in claim 1, further comprising: a baseplate, a table-plate slidably resting upon the base-plate and rotatable about the axis of the mandrel, means for rotating the table-plate along with the outer casing, the concentric rings that form the supporting surface being slidably rotatable upon the table-plate independently of one another, the cylindrical outer casing resting upon the tableplate near its outer edge, said casing being formed with a plurality of vertical slots extending downwards from its upper edge through which said magnets extend and said magnets being vertically displaceable in said slots so as to be able to rest freely upon the upper edges of the outermost turns of a coil of strip disposed in said casing.

3. Apparatus for the conversion of a tight coil of magnetizable steel strip into an expanded coil with spaced turns as claimed in claim 1, further comprising driving means, such as a spindle drive actuated by the rotary motion of the casing, for moving said magnets radially inwards as the radial dimension of the expanding coil progressively increases.

4. Apparatus for the conversion of a tight coil of magnetizable steel strip into an expanded coil with spaced turns as claimed in claim 2, further comprising means for releasably fixing said magnets in adjusted vertical position in said slots.

5. Apparatus for the conversion of a tight coil of magnetizable steel strip into an expanded coil with spaced turns as claimed in claim 1, said magnets being withdrawable radially outwards to enable a coil to be put into the apparatus and removed therefrom.

6. A method of expanding a tight coil of magnetizable metal strip to provide an expanded coil having substantially uniform spacing between adjacent turns, said method comprising the steps of disposing a tight coil of metal strip on end, fixing of the inner end of said coil against movement, disposing of the outer end of said coil at a point spaced from the axis of said coil a distance substantially equal to the desired radius of the expanded coil, rotating said outer end about said axis in a direction opposite to the winding direction of said coil to progressively unwind said coil with adjacent turns moving radially outwards toward said outer end, and progressively magnetizing with light polarity one edge of said outwardly moving turns,'whereby adjacent turns will repel each other with equal force to provide an expanded coil having substantia-ly uniform spacing between adjacent turns.

References Cited by the Examiner UNITED STATES PATENTS 2,366,352 l/l945 Paxson 24278.l 3,008,663 11/1961. Blackman et al. 24278.1 X 3,064,918 11/1962 Keen et a1 24278.1

MERVIN STEIN, Primary Examiner.

STANLEY N. GILREATI-I, Examiner.

N. L. MINTZ, Assistant Examiner. 

6. A METHOD OF EXPANDING A TIGHT COIL OF MAGNETIZABLE METAL STRIP TO PROVIDE AN EXPANDED COIL HAVING SUBSTANTIALLY UNIFORMA SPACING BETWEEN ADJACENT TURNS, SAID METHOD COMPRISING THE STEPS OF DISPOSING A TIGHT COIL OF METAL STRIP ON END, FIXING OF THE INNER END OF SAID COIL AGAINST MOVEMENT, DISPOSING OF THE OUTER END OF SAID COIL AT A POINT SPACED FROM THE AXIS OF SAID COIL A DISTANCE SUBSTANTIALLY EQUAL TO THE DESIRED RADIUS OF THE EXPANDED COIL, ROTATING SAID OUTER END ABOIUT SAID AXIS IN A DIRECTION OPPOSITE TO THE WINDING DIRECTION OF SAID COIL TO PROGRES- 